Once upon a time, Chuang Tzu dreamed that he was a butterfly, flying about enjoying itself. It did not know that it was Chuang Tzu. Suddenly he awoke, and veritably was Chuang Tzu again. He did not know whether it was Chuang Tzu dreaming that he was a butterfly, or whether it was the butterfly dreaming that it was Chuang Tzu. Between Chuang Tzu and the butterfly there must be some distinction. This is a case of what is called the transformation of things.

Discussion: "This shows that, although in ordinary appearance there are differences between things, in delusions or in dreams one thing can also be another. The transformation of things proves that the differences among things are not absolute "